Surface self-diffusion behavior of a Pt adatom on Wulff polyhedral clusters
作者：
Yang, Jianyu* ;Hu, Wangyu;Chen, Shuguang;Tang, Jianfeng
期刊：
Journal of Physical Chemistry C ,2009年113(52):21501-21505 ISSN：1932-7447
通讯作者：
Yang, Jianyu
作者机构：
[Yang, Jianyu] Hunan Inst Engn, Dept Math & Phys, Xiangtan 411104, Peoples R China.;[Hu, Wangyu; Chen, Shuguang] Hunan Univ, Dept Appl Phys, Changsha 410082, Hunan, Peoples R China.;[Tang, Jianfeng] Hunan Agr Univ, Dept Appl Phys, Changsha 410028, Hunan, Peoples R China.
通讯机构：
[Yang, Jianyu] H;Hunan Inst Engn, Dept Math & Phys, Xiangtan 411104, Peoples R China.
摘要：
The surface diffusion of a single Pt adatom on Wulff polyhedral clusters with 586-9201 atoms is studied, through a combination of the molecular dynamics and nudged elastic band methods. Interatomic interactions are modeled by the embedded atom method. The minimum energy paths are determined, and the energy barriers for an adatom diffusing on the Wulff polyhedral surface are evaluated. Within the studied cluster size range, the energy barrier for an adatom diffusing from the {111} to {100} facet increases with increasing cluster size. From the calculated energy barriers, we conclude that the Wulff polyhedral cluster is the most stable fcc structure, as the cluster has more than about 2000 atoms at 0 K. The calculated characteristic temperatures show that larger icosahedral or octahedral clusters could be formed at higher temperature. In addition, the static and dynamic simulations show that the diffusion from {111} to a neighbor {111} facet is slower than the diffusion from the {111} to {100} facet. ©2009 American Chemical Society.
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英文
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利用迈克尔孙干涉法测固体的线膨胀系数
作者：
王勇;汤剑锋;谭玉
期刊：
中国教育技术装备 ,2009年(6):105 ISSN：1671-489X
作者机构：
湖南农业大学理学院应用物理系,长沙,410126
关键词：
激光;迈克尔孙干涉法;线膨胀系数
摘要：
利用迈克尔孙激光干涉法测量固体的线膨胀系数,实验结果与理论值的相对偏差在5%以内。
语种：
中文
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激光干涉法测固体的线膨胀系数
作者：
王勇;汤剑锋
期刊：
湖南文理学院学报(自然科学版) ,2009年21(03):48-49 ISSN：1672-6146
作者机构：
湖南农业大学,应用物理系,湖南,长沙,410128
关键词：
线膨胀系数;迈克尔逊;激光;干涉法
摘要：
给出了一种利用迈克尔逊激光干涉法测量铜棒线膨胀系数的实验设计及其操作方法.采用激光干涉法测量材料线膨胀系数和传统的顶杆法相比具有测量准确,测量分辨率高等优点,特别适合于对线膨胀系数较低的固体材料进行测量.
语种：
中文
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MATLAB在“简谐运动的合成”教学中的应用
作者：
欧阳锡城;谭玉;汤剑锋
期刊：
云梦学刊 ,2008年(F07):149-150 ISSN：1006-6365
作者机构：
湖南农业大学理学院,湖南长沙410128
关键词：
简谐运动;合成;拍;李萨如图形
摘要：
本文用MATLAB软件编写了几段程序来模拟不同情况下简谐运动合成的图像,使教学内容变得更为形象、生动.>>详细
语种：
中文
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Diffusion Dynamics of Cu_x Cluster on Cu(111) Surface
作者：
Tang, Jian-Feng* ;Xu, Mai-Chang;Li, Xue-Song;Long, Wo-Yun
期刊：
化学物理学报(英文版) ,2008年21(1):27-31 ISSN：1674-0068
通讯作者：
Tang, Jian-Feng
作者机构：
[Tang, Jian-Feng; Li, Xue-Song; Long, Wo-Yun] Hunan Agr Univ, Dept Appl Phys, Changsha 410128, Peoples R China.;[Xu, Mai-Chang] Hunan Inst Engn, Dept Math & Phys, Xiangtan 411104, Peoples R China.
通讯机构：
[Tang, Jian-Feng] H;Hunan Agr Univ, Dept Appl Phys, Changsha 410128, Peoples R China.
关键词：
Cluster;Molecular dynamics;Surface diffusion
摘要：
The diffusion dynamics of small two-dimensional atomic clusters Cu x (1 x 8) on Cu(111) surface were studied using the molecular dynamics simulations and a modified analytic embedded-atom method in the temperature range from 200 K to 800 K. The cluster size and temperature dependence of the diffusion coefficients and migration energies are presented. Our simulations show that the diffusion migration energy of the Cu7 cluster is the highest and the prefactor for the Cu7 cluster is almost three orders of magnitude larger than that for single atom diffusion. This conclusion is consistent with the experimental results for similar metals. In addition, the dependence of cluster diffusion on film growth is also discussed. © 2008 Chinese Physical Society.
语种：
英文
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Vibrational properties in nanocrystalline nickels: temperature effects and composite model for thermodynamics
作者：
Tang, Jian-Feng* ;Li, Xue-Song;Long, Wo-Yun;Wang, Yong
期刊：
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS ,2008年245(8):1527-1533 ISSN：0370-1972
通讯作者：
Tang, Jian-Feng
作者机构：
[Tang, Jian-Feng; Li, Xue-Song; Long, Wo-Yun; Wang, Yong] Hunan Agr Univ, Dept Appl Phys, Changsha 410128, Hunan, Peoples R China.
通讯机构：
[Tang, Jian-Feng] H;Hunan Agr Univ, Dept Appl Phys, Changsha 410128, Hunan, Peoples R China.
关键词：
63.20.−e;63.22.+m;71.15.Pd
摘要：
Based on the atomic local structure, a nanocrystalline material is separated into two parts: inner grains and grain boundaries. Molecular dynamics simulations have been performed to study the difference in their vibrational properties in nanocrystalline nickels. The results obtained reveal that a similar phonon frequency softening as in the perfect lattice mainly focuses on grains in nanocrystalline materials, and for the grain boundary part there is no obvious change in the vibrational density of states in the temperature range 300-900 K, especially in the lower frequency range. Comparing with conventional crystals, the higher specific heat and vibrational entropy, and lower vibrational free energy with decreasing mean grain size, result from the high proportion of grain boundaries in nanocrystals. In addition, the composite model provides a good description of the contributions of grain and grain boundary phases to thermodynamic quantities. Supposing the nanocrystalline material can be treated as a composite composed of grain and grain boundary network, the vibrational thermodynamic quantities of the system can be well determined from the proportion of grain boundaries and the corresponding thermodynamic quantities of grain and grain boundary parts. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
语种：
英文
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Fast-response and high sensitivity gas sensors based on SnO2 hollow spheres
作者：
Tan, Yu* ;Li, Chengchao;Wang, Yong;Tang, Jianfeng;Ouyang, Xicheng
期刊：
Thin Solid Films ,2008年516(21):7840-7843 ISSN：0040-6090
通讯作者：
Tan, Yu
作者机构：
[Tan, Yu; Li, Chengchao] Hunan Univ, Micronano Technol Res Ctr, Changsha 410082, Hunan, Peoples R China.;[Ouyang, Xicheng; Tan, Yu; Tang, Jianfeng; Wang, Yong] Hunan Agr Univ, Coll Sci, Changsha 410128, Hunan, Peoples R China.
通讯机构：
[Tan, Yu] H;Hunan Univ, Micronano Technol Res Ctr, Changsha 410082, Hunan, Peoples R China.
关键词：
Gas sensors;Hollow spheres;Recovery;Response;Sensitivity;SnO2
摘要：
SnO<sub>2</sub> hollow nanospheres have been synthesized by heat treatment of a mixture composed of SnCl<sub>4</sub> and carbon microspheres. The SnO<sub>2</sub> nanospheres are 100 nm in size and composed of large amount of SnO<sub>2</sub> nanocrystals with diameters of ~ 6 nm, which is close to two times of the Debye length of SnO<sub>2</sub>. It was found that the sensitivity to 1000 ppm ethanol obtained with SnO<sub>2</sub> hollow nanosphere-based sensors is as high as 75. The response and recovery time are only 4 and 10 s, respectively. Such excellent sensing properties can be ascribed to the small-size nanocrystals and porous structure of SnO<sub>2</sub> hollow nanospheres, which lead to large diffusion constant. ©2008 Elsevier B.V. All rights reserved.
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英文
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嵌入原子势的分子动力学并行算法研究
作者：
汤剑锋;谭玉;欧阳锡诚;杨学工
期刊：
湖南城市学院学报(自然科学版) ,2007年16(2):43-45 ISSN：1672-7304
作者机构：
湖南农业大学,应用物理系,长沙,410128
关键词：
作用力分解;分子动力学;嵌入原子势
摘要：
针对嵌入原子势,提出了1种新的并行分子动力学算法--作用力分解算法.并与另外2种并行算法进行了比较.作用力分解算法并行代码编写简单,不要求模拟区域具有规则形状.而测试并行后的速度表明,当计算的原子数目小于104数量级时,它是最佳的并行算法.
语种：
中文
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Anharmonic effects on B2–FeAl(110) surface: A molecular dynamics study
作者：
Tang, Jianfeng;Hu, Wangyu* ;Yang, Jianyu;Wu, Yurong
期刊：
Applied Surface Science ,2007年254(5):1475-1481 ISSN：0169-4332
通讯作者：
Hu, Wangyu
作者机构：
[Tang, Jianfeng; Wu, Yurong; Hu, Wangyu] Hunan Univ, Dept Appl Phys, Changsha 410082, Peoples R China.;[Tang, Jianfeng] Hunan Agr Univ, Dept Appl Phys, Changsha 410128, Peoples R China.;[Yang, Jianyu] Hunan Inst Engn, Dept Math & Phys, Changsha 410082, Peoples R China.
通讯机构：
[Hu, Wangyu] H;Hunan Univ, Dept Appl Phys, Changsha 410082, Peoples R China.
关键词：
AEAM;B2-FeAl(1 1 0);Molecular dynamics;Surface anharmonicity
摘要：
Using molecular dynamics simulations and the analytic embedded-atom method (AEAM), the surface anharmonicity of B2-FeAl(1 1 0) has been studied in the temperature range from 0 K to 1400 K. The temperature dependence of the interlayer spacing, mean square vibrational amplitudes, surface phonon frequencies and line-widths, and layer structure factor have been calculated. The obtained results indicate that the anharmonic effects are small in the temperature range from 0 K to 900 K. The temperature dependences of the interlayer spacing indicates that the rippling effect of the B2-FeAl(1 1 0) surface is exhibited by the contraction of Fe surface atoms and the expansion of Al atoms, which persists at high temperatures. The temperature dependence of the layer structure factors shows that the B2-FeAl(1 1 0) surface does not disorder until the temperature of 1300 K. © 2007 Elsevier B.V. All rights reserved.
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英文
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